DC Electric Fan

ABSTRACT

A direct-current (DC) electric fan configured for cooling purposes and for use in all places includes a base, a plurality of fixed-height interconnected inner and outer tubes extending upward from the base, and a driving motor provided in the base for driving the inner and outer tubes into reciprocal rotation, thereby simultaneously driving the fan unit mounted to each inner tube and between each two adjacent outer tubes to rotate over a predetermined rotation range. The blowing direction of each fan unit is also manually adjustable so that the blowing range of the fan can be adjusted and set according to personal needs.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention relates to a direct-current (DC) electric fan. More particularly, the present invention relates to a DC electric fan to be placed in all places in order to bring down ambient temperature, wherein a driving motor can drive an outer tube and thereby drive fan units arranged at a specific spacing to blow wind over a predetermined rotation range, and wherein the blowing direction of each fan unit is also manually adjustable so that the blowing directions of the fan can be adjusted and set flexibly.

2. Description of Related Art

Nowadays, electric fans for lowering indoor or outdoor temperature are available in a variety of configurations. The most common type of electric fans are those having a single fan unit and designed to blow wind over a predetermined rotation range and/or in fixed directions while positioned at fixed locations. Also available on the market are those having a plurality of DC fan units which are arranged side by side in a housing of a predetermined shape and whose blade rotation speeds and blowing angles are individually adjustable. Alternatively, the plural fan units are installed side by side on a support so that the blowing range and blowing direction of each fan unit can be adjusted independently.

While all the foregoing fans, whether single or multiple fan unit-based, are adjustable to preset blowing directions or the desired blowing power, directional adjustment of the multiple fan units must be driven by a motor axle and cannot be done by hand.

BRIEF SUMMARY OF THE INVENTION

The present invention provides an improvement over the direction adjustment mechanism of existing electric fans that are designed for cooling purposes. It is desirable that the driving motor of an electric fan can drive an outer tube and thereby drive each of a plurality of fan units arranged at a predetermined spacing to rotate over a predetermined rotation range. It is also desirable that the blowing direction of each fan unit can be manually adjusted, so as to allow flexible adjustment and control of the blowing directions of the fan.

The primary object of the present invention is to provide an electric fan which includes a base, a plurality of fixed-height interconnected inner and outer tubes extending upward from the base, and a driving motor provided in the base. The driving motor is configured for driving the inner and outer tubes into reciprocal rotation and thereby simultaneously driving the fan unit mounted to each inner tube and between each two adjacent outer tubes to rotate over a predetermined rotation range. The blowing direction of each fan unit is also manually adjustable so that the blowing range of the fan can be adjusted and set according to personal needs.

The second object of the present invention is to provide the foregoing electric fan, wherein the driving motor in the base transmits power through a connecting element to a lining block peripherally provided with plural grooves. Then, the lowermost outer tube, which is mounted around the lining block via the plural ridges formed on the inner periphery of the lowermost outer tube, delivers the power to the inner tubes to which fan units are mounted respectively. Each inner tube is connected with the adjacent upper and lower outer tubes by engagement between the engaging portions extending respectively from the upper and lower ends of each inner tube and the recesses formed respectively at the corresponding positions of the adjacent upper and lower outer tubes. Thus, the inner tubes and the outer tubes are interconnected for synchronous rotation, so as for the driving motor to drive the fan unit mounted to each inner tube and between each two adjacent outer tubes to rotate reciprocally over the predetermined rotation range.

The third object of the present invention is to provide the foregoing electric fan, wherein the inner tubes to which the fan units are mounted respectively are each concavely provided with a slot extending over a predetermined range. Each inner tube is also formed with a cavity located within the slot and having slightly protruding left and right edges. Meanwhile, each fan unit has a protuberance corresponding in position to and engageable in the cavity of the corresponding inner tube. A user can manually rotate any of the fan units according to the desired blowing direction so that the protuberance of the fan unit is disengaged from the cavity of the corresponding inner tube and moved to the center of a desired blowing range, thus allowing the fan unit to be driven by the driving motor to rotate over the desired blowing range.

The fourth object of the present invention is to provide the foregoing electric fan, wherein resilient rings are mounted around each inner tube at positions where each inner tube is connected with the adjacent upper and lower outer tubes. The resilient rings allow each inner tube and the adjacent upper and lower outer tubes to be securely engaged with each other.

The fifth object of the present invention is to provide the foregoing electric fan, wherein the plural interconnected inner and outer tubes extending upward from the base are topped with a push button unit for turning on and off the fan units and controlling the blowing power thereof

The sixth object of the present invention is to provide the foregoing electric fan, wherein the driving motor for driving the fan units is an eccentric motor. The eccentric motor has an axle connected with a swing arm for transmitting the power of the driving motor to the adjacent lining block and the lowermost outer tube, thereby delivering a predetermined rotation of the driving motor to each fan unit and causing each fan unit to rotate reciprocally in synchronization with the driving motor.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The structure as well as a preferred mode of use, further objects, and advantages of the present invention will be best understood by referring to the following detailed description of an illustrative embodiment in conjunction with the accompanying drawings, in which:

FIG. 1 is a perspective view of a DC electric fan according to the present invention;

FIG. 2 is an exploded perspective view of the DC electric fan according to the present invention;

FIG. 3 is a front view of the DC electric fan according to the present invention;

FIG. 4 is a schematic cross-sectional view taken along line 40-40 of FIG. 3;

FIG. 5 is a detailed cross-sectional view taken along line 40-40 of FIG. 3;

FIG. 6 is a schematic cross-sectional view taken along line 60-60 of FIG. 3;

FIG. 7 is a detailed cross-sectional view taken along line 60-60 of FIG. 3;

FIG. 8 is a schematic cross-sectional view taken along line 80-80 of FIG. 3;

FIG. 9 is a detailed cross-sectional view taken along line 80-80 of FIG. 3;

FIG. 10 is a schematic cross-sectional view taken along line 100-100 of FIG. 3; and.

FIG. 11 is a detailed cross-sectional view taken along line 100-100 of FIG. 3.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1 and FIG. 2, a direct-current (DC) electric fan 8 according to the present invention includes a plurality of interconnected inner and outer tubes 4, 5 provided on a base 1, wherein each inner tube 4 is mounted with a fan unit 6. A push button unit 7 for turning on and off the fan units 6 and controlling the blowing power thereof is installed at the upper end of the uppermost inner tube 4.

The power unit of the DC electric fan 8 is a driving motor 12 provided in the base 1, which in turn is supported on a seat 11. In this embodiment, the driving motor 12 is an eccentric motor. The connection between the driving motor 12, the inner and outer tubes 4, 5, and the fan units 6 is now described with reference to FIG. 2 and FIG. 3. The driving motor 12 has an axle 121 connected with a swing arm 13 (see FIG. 5) for transmitting power to a connecting element 14 and thereby transmitting the power to a lining block 2 connected to the connecting element 14, wherein the lining block 2 is peripherally provided with a plurality of grooves 21. The lowermost of the outer tubes 5, which is designated specifically by the reference numeral 3 and whose inner periphery is formed with plural ridges 31 corresponding in position to the grooves 21, is mounted around the lining block 2 via engagement between the ridges 31 and the grooves 21 so as to deliver the power further to the inner tube 4 corresponding to each fan unit 6, as shown in FIG. 7, FIG. 9, and FIG. 11. Each inner tube 4 has an upper end and a lower end, each of which ends is extended with an engaging portion 41. Meanwhile, each of the outer tubes 5 (including the lowermost outer tube 3) has recesses 51 (or 32) corresponding in position to the engaging portions 41. Each inner tube 4 is connected with two adjacent outer tubes 5 (one of which can be the lowermost outer tube 3, and which are hereinafter generally referred to as the adjacent upper and lower outer tubes 5) via engagement between the engaging portions 41 and the corresponding recesses 51 (and 32), as shown in FIG. 2. Thus, the inner tubes 4 and the outer tubes 5 (including the lowermost outer tube 3) are interconnected for synchronous rotation, so as for the driving motor 12 to drive the fan units 6, which are mounted to the inner tubes 4 and between the adjacent upper and lower outer tubes 5 respectively, to rotate reciprocally over a predetermined rotation range.

As shown in FIG. 2 and FIG. 7, each inner tube 4 is concavely provided with a slot 42 extending over a predetermined range. Each inner tube 4 also has a cavity 43 formed within the slot 42 and having slightly protruding left and right edges. Referring to FIG. 9, a protuberance 62 formed on a tube section 61 of each fan unit 6 is engageable in the cavity 43 of the corresponding inner tube 4. In addition, referring to FIG. 2, resilient rings 52 are mounted around the inner tube 4 of each fan unit 6 at positions where the inner tube 4 is connected with the adjacent upper and lower outer tubes 5, with a view to enhancing the engagement between the connecting portions of the inner and outer tubes 4, 5. The push button unit 7 is located at the top end of the plural interconnected inner and outer tubes 4, 5 extending upward from the base 1 and is configured to turn on and off the fan units 6 and control the blowing power thereof.

The driving motor 12 in the base 1, the plural interconnected inner and outer tubes 4, 5, the plural fan units 6, and the push button unit 7, which jointly constitute the major portion of the electric fan 8, operate in the following manner. Referring to FIG. 3 through FIG. 5, once the driving motor 12 is activated by operating the push button unit 7 at the top end of the electric fan 8, the driving motor 12 transmits power through the swing arm 13 to the adjacent lining block 2 and the lowermost outer tube 3 (see FIG. 5). Thus, the driving motor 12 delivers a predetermined rotating motion (e.g., successive clockwise and counterclockwise rotation of 30 degrees) to each fan unit 6, and the fan units 6 are synchronously driven into reciprocal rotation (see FIGS. 6 and 7 for the lowermost fan unit 6, FIGS. 8 and 9 for the middle fan unit 6, and FIGS. 10 and 11 for the uppermost fan unit 6). More particularly, with the protuberance 62 on the inner wall of the tube section 61 of each fan unit 6 being engaged in the cavity 43 in the slot 42 of the corresponding inner tube 4 (as shown in FIG. 9), the fan units 6 are driven to rotate over the predetermined rotation range while the inner tubes 4, which are connected either directly or indirectly to the lowermost outer tube 3, are driven by the driving motor 12 to rotate reciprocally.

When it is decided that any of the fan units 6 (e.g., the uppermost, middle, or lowermost fan unit 6) need not be rotated over the entire predetermined rotation range, the fan unit 6 can be manually rotated so that the protuberance 62 of the fan unit 6 is driven out of the cavity 43 of the corresponding inner tube 4 (see FIG. 7 and FIG. 11) and moved to the central position of a desired blowing range as limited by the corresponding slot 42. (In the present embodiment, the protuberance 62 once disengaged from the cavity 43 can be moved to the left or to the right by up to 90 degrees.) Thus, the fan unit 6 whose protuberance 62 is freed from the cavity 43 of the corresponding inner tube 4 can be driven by the driving motor 12 to rotate over the desired blowing range. This technical feature allows the blowing range of the electric fan 8 to be adjusted and set according to personal needs. 

1. A direct-current (DC) electric fan, comprising: a base, a plurality of fixed-height interconnected inner and outer tubes extending upward from the base, and a driving motor provided in the base for driving the inner and outer tubes into reciprocal rotation and thereby simultaneously driving a fan unit mounted to each said inner tube and between each two adjacent said outer tubes to rotate over a predetermined rotation range, wherein each said fan unit is also manually adjustable to a desired blowing direction such that a blowing range of the electric fan can be adjusted and set as needed.
 2. The DC electric fan of claim 1, further comprising a push button unit mounted at an upper end of the interconnected inner and outer tubes and configured for turning on and off the fan units and controlling a blowing power thereof
 3. The DC electric fan of claim 1, wherein the driving motor in the base transmits power to the inner tube corresponding to each said fan unit sequentially through a connecting element, a lining block connected to the connecting element and peripherally provided with a plurality of grooves, and a lowermost said outer tube mounted around the lining block via engagement between a plurality of ridges formed on an inner periphery of the lowermost outer tube and the grooves of the lining block, each said inner tube being connected with adjacent upper and lower said outer tubes via engagement between engaging portions which extend respectively from an upper end and a lower end of each said inner tube and recesses which are provided on the adjacent upper and lower outer tubes and correspond in position to the engaging portions, thus allowing the interconnected inner and outer tubes to rotate simultaneously and thereby drive the fan units to rotate reciprocally over the predetermined rotation range.
 4. The DC electric fan of claim 3, further comprising a push button unit mounted at an upper end of the interconnected inner and outer tubes and configured for turning on and off the fan units and controlling a blowing power thereof
 5. The DC electric fan of claim 3, wherein each said inner tube is concavely provided with a slot extending over a predetermined range and a cavity formed within the slot and having slightly protruding left and right edges, and each said fan unit has a protuberance corresponding in position to and engageable in the cavity of a corresponding said inner tube, each said fan unit being manually rotatable according to the desired blowing direction so that the protuberance of the fan unit is driven out of the cavity of the corresponding inner tube and moved to a central position of a desired blowing range, thus allowing the fan unit to be driven by the driving motor to rotate over the desired blowing range.
 6. The DC electric fan of claim 3, wherein resilient rings are mounted around each said inner tube at positions where each said inner tube is connected with the adjacent upper and lower outer tubes respectively, thus enhancing engagement between connecting portions of each said inner tube and the adjacent upper and lower outer tubes.
 7. The DC electric fan of claim 3, wherein the driving motor for driving the fan units is an eccentric motor, and an axle of the eccentric motor is connected with a swing arm for transmitting power to the lining block and the lowermost outer tube, delivering a predetermined rotation of the driving motor to each said fan unit, and thus simultaneously driving each said fan unit into reciprocal rotation. 